The integrity of hermetic seals for integrated circuit packages is vital for high reliability integrated circuits such as those used by the military. Traditionally, quality control standards require that integrated circuit packages be 100% hermetically sealed. Over the past few decades, many tests have been developed for the purpose of proving the credibility of integrated circuits. Air-tight or hermetic packages for integrated circuits have been particularly useful, as it has been possible to test for hermetic seals. These hermetic testing procedures, however, are time consuming and require extensive governmental involvement to enforce the safety standards placed on the industry.
Additionally, the integrated circuit industry has not been completely successful in testing integrated circuits economically in high volume production. One previous testing method involved a leak test using radioactive krypton-85 gas. Helium has also been employed; however, krypton-85 has a higher detectibility than helium when used as the leak detection media. Despite this advantage of krypton-85 over helium, krypton-85 has a relatively low gamma-ray emission and thus is not a fully successful testing media.
Governmental regulation has required users to take extensive safety precautions when handling krypton-85, since krypton-85 has a radioactive half-life of approximately 10.8 years. Governmental agencies generally shut down testing facilities when krypton-85 is detected in the atmosphere, and thus prior radioactive gas testing has been quite expensive.
A need has therefore arisen for a hermetic testing apparatus and process for integrated circuits which is cost effective for high volume production, has the advantage of high gamma-ray emission for the detection of leaks, and is relatively safe to operate.